HFSS Simulation Research Articles

Waves in frequency-independent single-mode 2-D artificial media with forced refraction

Investigations of the waves in planar structures with anisotropic gratings proved that structures of this type demonstrated properties of 2D media with forced refraction. Parasitic modes and limited frequency range were typical for them. This study investigated the propagation of guided waves along metal grating lying between two metal screens inside parallel plate waveguide (PPW). Dominant T-mode was the focus of this study. This mode was studied theoretically by the method of integral equations (IE) and numerically with the help of an electromagnetic Ansys HFSS simulation. Both methods demonstrated that the investigated structure had the properties of a 2D medium with forced refraction independent of frequency. The modified structure contained metal grating and an additional 2D array of metal cylinders was also studied numerically. The numerical simulation demonstrated that an array of metal cylinders suppressed parasitic PPW mode and thus modified structure demonstrated properties of a single-mode frequency independent artificial media with forced refraction. The results have the potential for application in microwave and millimeter-wave planar quasi-optical lens antennas.

Realizing the High Q-Factor of a CSIW Microwave Resonator Based on an MDGS for Semisolid Material Characterization.

In this work, the high-quality factor (Q-factor) and high sensitivity of a circular substrate-integrated waveguide (CSIW) are proposed for the characterization of semisolid materials. The modeled sensor was designed based on the CSIW structure with a mill-shaped defective ground structure (MDGS) to improve measurement sensitivity. The designed sensor oscillates at a single frequency of 2.45 GHz, which was simulated using an Ansys HFSS simulator. Electromagnetic simulation explains the basis of the mode resonance of all two-port resonators. Six variations of the materials under test (SUTs) were simulated and measured, including air (without an SUT), Javanese turmeric, mango ginger, black turmeric, turmeric, and distilled water (DI). A detailed sensitivity calculation was performed for the resonance band at 2.45 GHz. The SUT test mechanism was performed using a polypropylene tube (PP). The samples of dielectric material were filled into the channels of the PP tube and loaded into the center hole of the MDGS. The E-fields around the sensor affect the relationship with the SUTs, resulting in a high Q-factor value. The final sensor had a Q-factor of 700 and a sensitivity of 2.864 at 2.45 GHz. Due to the high sensitivity of the presented sensor for characterization of various semisolid penetrations, the sensor is also of interest for accurate estimation of solute concentration in liquid media. Finally, the relationship between the loss tangent, permittivity, and Q-factor at the resonant frequency were derived and investigated. These results make the presented resonator ideal for the characterization of semisolid materials.

Low-Cost Electromagnetic Absorbers for Shield Packaging

In this paper a low-cost solution to tackle the problem of electromagnetic interference (EMI) is proposed for shield packaging industry. The absorber consists of circularly shaped frequency selective surface (FSS) based structure engraved on an acrylic sheet. Each unit cell of the absorber structure is filled with Plaster of Paris (POP) as a dielectric material backed with a copper foil acting as ground plane. The top of this FSS based structure is covered with a thin sheet of acrylic sheet. The periodicity of the unit cell is 0.4λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> and the thickness of the absorber is only 0.12λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> , where λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> is the wavelength of free space at the lowest absorbing frequency. A polarization independent behaviour of the absorber is depicted up to 45° angles of incidence. A detailed parametric study is carried out on HFSS simulation tool, and a prototype model is developed. Finally, the simulated result is verified with measured results which shows a good agreement between the two. It is found that the proposed absorber structure provides a viable solution for absorbing the EMI at X-band.

On the Sensitivity of the Daily Mean Air Temperature of Egypt to Boundary Layer Schemes Using a High-Resolution Regional Climate Model (RegCM4)

Introduction: Boundary layer processes play an important role in controlling the daily mean air temperature through exchange of turbulent fluxes of water and energy between the ground surface and the atmosphere. Therefore, it is important to explore the role of boundary layer parameterization in simulating the daily mean air temperature particularly on a regional scale. Methods: To accomplish this task, two simulations were conducted to assess the sensitivity of the mean air Temperature (TMP) of Egypt to boundary layer schemes (Holtslag; HOLT and University of Washington; UW) within the framework of the Regional Climate Model (RegCM4). The RegCM4 was downscaled by the ERA-Interim reanalysis of 1.5 degrees with 25 km horizontal grid spacing over the period 1997-2017. Additionally, ERA5 reanalysis product was used as the observational dataset for the variables: the Total Cloud Cover (CLT), surface short and long wave radiation fluxes (RSDS and RLDS), Skin Temperature (TS), surface Wind Speed (WS), Sensible Heat Flux (HFSS) and TMP. Results: There is no difference between HOLT and UW regarding the CLT and RSDS; while the UW reduces the bias of the RLDS and WS relative to HOLT particularly in the summer and autumn seasons in comparison with ERA5. Furthermore, HOLT and UW schemes showed a considerable impact on the simulated TS. For instance, UW reduces the TS bias relative to HOLT in all seasons but in the spring and winter seasons; UW induces a negative bias more than HOLT. Concerning the HFSS, UW shows a higher bias than HOLT mainly in the summer and autumn seasons. Because of the noted changes of the simulated HFSS and TS, the UW succeeds in reducing the warm bias of the TMP (noted in the HOLT) in all seasons in comparison with the ERA5. With respect to in-situ observations, the HOLT/UW performance varies with the location as well as the month. Conclusion: The UW scheme can be recommended for future studies concerning the future climate change of Egypt concerning the regional scale. However for a point scale, caution is needed in interpreting the results with respect to the in-situ observations except for Asswan where HOLT can be recommended.

Co-deposition of C and Ni[sbnd]P to fabricate high-ohmic resistor for board-level integration with on-line monitoring method

Embedding thin–film resistance (ETFR) in printed circuit boards (PCB) is of great significance for precise circuit designing and is thus widely applied in analogous circuits. This work introduces diethylenetriamine (DETA) into NiP electroless-plating solution to obtain C-doped NiP high-ohmic value resistor with square resistance over 400 Ω/sq. During the deposition, a referred resistor is monitored on-line to indicate the resistance of other embedded resistors, achieving a confined resistive error within ±10 %. This reduced resistive error primely satisfies the developing demand for the effective transmission of signal. The effects of DETA content, temperature and pH values on resistances were studied to optimize the Ni-P-C composition, yielding the highest ohm value of 731 Ω/sq. Rectangular and serpentine resistors with varied sizes were fabricated to confirm the realizability of this proposed method. The results of experiments including lamination processing and temperature coefficient of resistance (TCR) tests suggest the thermal as well as mechanical stability of the fabricated embedded resistor for PCB manufacture. The HFSS simulation for comparison between the parasitic effects of surface mounted technology resistor (SMTR) and ETFR indicates that the prominent performance of the developed resistor is compatible with ETFR components.

An Ultra-Thin, Triple-Band, Incident Angle-Insensitive Perfect Metamaterial Absorber.

We created an ultra-thin, triple-band incident angle-insensitive perfect metamaterial absorber (MMA) with a metallic patch and a continuous metal ground isolated by a central dielectric substrate. The top metallic patch, placed across the edges of the 0.58 mm thickness Rogers RO4003C (lossy) substrate, forms the bulk of the projected absorber's ultra-thin layer. Nonetheless, absorption is exceedingly strong, covering C-band, X-band and K-band and reaching levels of 97.8%, 99.9%, and 99.9%, respectively, under normal and even oblique (0° to 45°) incident conditions. In chosen ranges of frequency of 6.24, 10.608, and 18.624 GHz for both TM and TE mode, the displayed Q-factors were 62.4, 17.68, and 26.61, respectively. We correspondingly calculated the RAB (relative absorption bandwidth) to evaluate absorption performance. An equivalent circuit proved its performance capabilities, indicating that it would produce a high-quality MMA from ADS software. Furthermore, the absorber's performance has been verified in free space on a sample being tested using a different array of unit cells. Moreover, the proposed structures with HFSS simulators to display the MMA's absolute absorption at each absorption peak are somewhat inconsistent with the results of the CST simulator. Because of its superior performance, the ultra-thin absorber is suited for a wide range of applications, including satellite applications such as radar systems, stealth technology, imaging, and electromagnetic interference reduction.

Compact high-selective wide-stopband coupled bandpass filter using middle-shorted hairpin-resonators

In this letter, a novel compact highly selective coupled bandpass filter (BPF) with sharp roll-off and wide stopband with excellent attenuation is proposed. This BPF is designed using two middle-shorted hairpin-resonators and a slot line resonator. The coupling matrix is calculated theoretically as per the specifications. The coupling coefficients between the resonators are computed by using the full-wave simulator HFSS to properly select the coupling gap between the resonators. The ABCD and S-parameters of the proposed design are computed, and the S-parameters are plotted theoretically. The designed filter is fabricated and tested. Good agreement is found between simulation and measurement. The proposed filter has excellent measured characteristics, including an insertion loss of 1.2 dB, a return loss better than −20 dB, high band edge attenuation of 60 dB, three Transmission Zeros (TZs), and a wide stopband rejection of greater than 30 dB up to 3f0 where f0 is the center frequency of the BPF. The proposed filter can be used for WLAN applications.

Antenna Array on Glass Interposer for 6G Wireless Communications

This paper demonstrates integrated packaging solutions for antenna components in D-band by using glass-based package. We design sub-terahertz patch antennas at 140 GHz frequency band using HFSS simulation, and form arrays of patch antennas for 6G (sub-THz) wireless communication applications. The patch antennas and feeding networks are implemented using microstrip structures on the top of the interposer, with ground planes beneath. Build-up layers of polymer dry films are laminated on a glass core for multi-layer copper metallization, and copper structures are patterned on the polymer layers. For precise fabrication of the antenna and feeding structures in package, we implement the semi-additive patterning process to deposit the copper structures. Adequate measurement methods are applied to address difficulties in D-band antenna measurements. By forming patch antenna arrays, we obtain 10 dBi gain using a 4-element linear array and 14 dBi gain using a 4-by-4 2-D array. The bandwidths achieved for these arrays are 7% (10 GHz) and 5% (7 GHz), respectively, based on return loss measurements. Overall, the measurement results present good match to simulation. Antenna structures on glass substrates demonstrated in this paper represent the basic building block for heterogeneous integration of D-band front-end module in glass-based packages.

LOW-COST C-BAND SIW BANDPASS FILTER USING FR4-EPOXY SUBSTRATE

This paper describes a substrate integrated waveguide (SIW) filter built on an Fr4-Epoxy substrate with a dielectric constant 4.4 and a height of h=1.6mm. SIW-based devices have piqued the interest of researchers in recent years due to their low loss, small size, and low cost. The goal is to simulate and realize a SIW filter for C-band applications. The designed filter is analyzed using the reflection coefficient S11 and electric field distributions. We used the HFSS simulator. According to the findings, there is a high degree of agreement between the simulated and realized filters. The results also show that the filter has a very good response. It also shows a bandwidth of 6.3GHz around the C-band frequencies. This filter's pass-band ranges from 5.39 to 6.83GHz, with an insertion loss of 4.2dB and a return loss of 45.49dB.

Designing of ground slotted circular ring patch antenna for X band using ANSYS HFSS Simulator

Designing of ground slotted circular ring patch antenna for X band using ANSYS HFSS Simulator

Design and Comparison Study of Circular and Elliptical Microstrip Patch Antennas for 5G Applications

In this paper, the designs and performances of coaxial fed circular and elliptical microstrip patch antennas operating at 28 GHz and 38 GHz are investigated using CST and HFSS simulation techniques. The substrates used in the designs are Rogers-RT-5880, RT-Duroid-6002 and FR-4 with a same thickness of (h=0.2 mm). To identify the optimum radiation performance, a comparison for the fundamental parameters of the designed CMSPA and EMSPA are conducted. The numerical results show that although the CMSPA has a smaller patch area, its radiation performance is lower than the EMCPA. Moreover, the RT-Duroid-6002 substrate maintains the optimum radiation characteristics for the designed antennas, at which the EMSPA gain, directivity, S11 and BW values at 28 GHz and 28 GHz are (6.86 dB, 7.37 dB), (7.28 dB, 7.61 dB), (-23.14 dB, -19.23 dB), and (0.749 GHz, 1.300 GHz). While for CMSPA, their values are (6. 41 dB, 6.60 dB), (6.92 dB, 6.90 dB), (-19.11 dB, -12.50 dB), and (0.717 GHz, 1.077 GHz). The performances of the designed antennas are compared with the previously published works, and very good agreements are achieved. Finally, the designation of EMSPA which slightly studied at (38 GHz) shows a suitable antenna parameter reliable for many 5G applications systems.

Passive RFID microstrip photosensitive sensor based on TiO2/rGO/CuO composite

In this paper, a passive RFID microstrip antenna photosensor based on titanium dioxide (TiO2)/reduced graphene oxide (rGO)/copper oxide (CuO) nanocomposite was designed and fabricated for monitoring light intensity in the environment. The microstrip patch antenna with slot is designed by HFSS simulation, the actual antenna is prepared by the engraving machine, and the photosensitive RFID sensor is prepared by coating the nano-material on the antenna by drop coating. The amplitude of ambient light intensity is determined in the frequency band of 2.082 GHz–2.087 GHz. To study its performance, the sensor coated with the sensitive material was tested under a solar simulator. The results show that from the dark environment (0 klx)-32.9 klx light intensity, the sensitivity of the photosensor is 0.106 ± 0.03 db/klx, and the sensitivity is 0.784 ± 0.08 db/klx under the light intensity of 36.8–53.9 klx. The response time of the photosensor was 20.1 s and the recovery time was 30.3 s in the light intensity range of 0–53.9 klx, indicating that the TiO2/rGO/CuO composite has good responsiveness and repeatability as a photosensitive material.

Detection Method Based on RFID Tag on the Metal Surface

In radio frequency identification (RFID) technology, RFID tags’ work on the metal surface is greatly affected by the metal, and the read/write distance and read rate of the tag will be reduced along with the change of the distance between the tag and the metal surface. Aiming at this feature, this paper studies and designs two kinds of metal-resistant UHF RFID micro-strip tags with a center frequency of 915MHz according to the “resonant cavity principle” and HFSS simulation software. After optimization, the size of the tag antenna is reduced. Through the distance expression and experiment, we verify the maximum recognition distance between the reader, and the tag can reach 3.46m, which can solve the problem of conventional RFID tags by metal interference.

Miniaturized Antenna for IOT Application

Ansys platform-based HFSS simulator software is used to create a 4GHz circular micro strip patch antenna array. Applications including Bluetooth, the Internet of Things, and several WLANs can all benefit from it. The circular patch antenna, which is constructed on a FR4 substrate with a dielectric constant of 4.4 and a height of 1.6mm, is fed using edge feeding. The antenna is built using a 1.4mm thick FR-4 (lossy) substrate with a relative permittivity of 4.4 and a microstrip line feed. The chosen radius for the circular patch is 7.62mm. To lower the size and enhance the performance of the suggested antenna, a square slit 30mm by 30mm in size is etched onto the ground plane. The HFSS Simulation Program is employed in the antenna's design. Antenna characteristics such as return loss, radiation pattern, bandwidth, orientation, antenna gain and radiated efficiency are all studied.

Development of a compact transverse slot array antenna using corrugation in groove gap waveguide technology

SummaryWe present the proof of concept of a compact slot array antenna with proper side lobe level in groove gap waveguide (GGW) technology. Four transverse slots are etched at the GGW broad wall along with the nulls of standing TE10 wave existing inside the shorted GGW. To decrease the sidelobes and antenna size, corrugations are applied through the wave path inside the GGW. Proper use of corrugations can reduce the wavelength inside the GGW leading to reduction of the distance between adjacent transverse slots, which can help to suppress the grating lobe problem and consequently enhance the radiation efficiency, which is a challenge in transvers slot array antennas. The designed antenna is optimized to achieve maximum gain, lowest grating lobe level, and return loss at 15 GHz using HFSS simulator. The achieved gain is about 13 dBi, and the SLL is better than 15 dB. To confirm the simulation results, the designed antenna was fabricated and tested. Both simulation and measurement results confirm that the grating lobes are well suppressed at the antenna operating frequency.

Fabrication of On-Silicon Aperture Coupled Patch Antenna Through Micromachining and Cu-Cu Thermocompression Bonding

This paper, for the first time, reports the fabrication of an on-Silicon aperture-coupled 3D Patch antenna using micromachining and low-temperature, low-pressure Copper(Cu)-Copper(Cu) thermo-compression bonding. Micromachining technique was used to reduce the effective dielectric constant of Silicon (Si), thereby increasing the radiation efficiency. One of the main challenges in fabricating the aperture coupled patch antenna on Si is the realization of its 3D structure. The top and bottom substrates of the 3D antenna have to be bonded together without disturbing the micromachined thin membrane. This was achieved using thermo-compression bonding under optimized temperature and pressure conditions with a 3 nm Gold (Au) passivation layer, which prevents the oxidation of the Cu layer underneath and thereby reducing the inter-diffusion barrier across the interface. The proposed fabrication process flow introduces the novelty of using bonding/stacking metal inter-layer as the common ground of the antenna. The device was fabricated on high resistivity Si wafers to minimize the conduction losses. Herein, we have fabricated an aperture coupled 3D patch antenna with a cavity depth of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$200\pm ~10\mu \text{m}$ </tex-math></inline-formula> , and the device characteristics were compared with the HFSS simulation results. The reliability of the fabricated antenna was assessed by bond strength analysis, cross sectional FESEM and TEM imaging. The on-chip antenna yielded a resonance frequency of 13.4 GHz, with VSWR 1.16. The radiation pattern of the antenna was also analyzed experimentally. This technology is the way forward to fabricating miniaturized high performance on-chip antennas.

Dual-Square-Split-Ring-Enclosed Microstrip-Based Sensor for Noninvasive Label-Free Detection.

In this article, we present the use of a metamaterial-incorporated microwave-based sensor with a single port network for material characterization. The proposed sensor consists of a microstrip patch layer enclosed with a dual-square-shaped metamaterial split-ring. This structure has the dimensions of 20 × 20 × 1.524 mm3 and a copper metallic layer is placed on a Rogers RT 6002 with a partial back layer as a ground. Two resonant frequencies are exhibited for applied electromagnetic interaction using a transmission line. The dual split rings increase the compactness and accumulation of the electromagnetic field on the surface of the conducting layer to improve the sensitivity of the sensor. The numerical studies are carried out using a CST high-frequency microwave simulator. The validation of the proposed sensor is performed with an equivalent circuit model in ADS and numerical high-frequency simulator HFSS. The material under test placed on the proposed sensor shows good agreement with the frequency deviation for different permittivity variations. Different substrates are analyzed as a host medium of the sensor for parametric analysis.

A wearable low profile asymmetrical slotted ultra-wide band antenna for WBAN applications

In this article a low profile asymmetrical slotted Ultra-Wide Band (UWB) antenna is proposed for Wireless Body Area Networks (WBANs) applications. The antenna was fabricated using Printed Circuit Boards (PCBs). An improved radiation pattern was obtained with an optimized patch shape of the antenna that broadens the bandwidth and lowers the antenna’s profile. The proposed antenna is simulated in HFSS and CST Simulator, and the proposed antenna is fabricated on FR4 substrate with the reduced ground plane. In frequency ranges from 2.50 to 10.97 GHz simulation as well as measured results show that the reflection coefficient (S11) of the antenna is below − 10 dB and increased impedance bandwidth of 126%. The proposed antenna has desired radiation pattern and gain for wearable application. The wearable performance of proposed antenna on chest, leg, and the arms of the human body is analyzed with Specific Absorption Rate (SAR). The maximum value of the SAR is 0.785 W/Kg which is less than threshold value of 1.6 W/kg. The time-domain behavior of proposed antenna is investigated with the time domain parameters such as Group delay, Fidelity factor and Mean realized gain. The time domain results are evident for the proposed antenna is capable of pulse signal transmission and reception.

Understanding the efficient microwave absorption for FeCo@ZnO flakes at elevated temperatures a combined experimental and theoretical approach

• ZnO coated flaky FeCo is successfully fabricated by a facile melting and ball milling strategy. • Considerable high-temperature absorption is achieved with broad bandwidth and thin thickness. • The attenuation mechanisms at high temperature have been detailedly studied for the first time. • The evolution of incident EM waves at high temperature is illustrated by HFSS simulation. Considerable microwave absorption performance at elevated temperatures is highly demanded in both civil and military fields. Single dielectric or magnetic absorbers are difficult to attain efficient and broadband microwave absorption at the high temperature range of 373 K–573 K, and the evolution mechanism of the microwave absorption is still unclear especially for the magnetic absorbers. Herein, ZnO coated flaky-FeCo composite is proposed to break through the bottleneck, which possesses microwave absorption (RL<-10 dB) that covering the whole X band (8.2 GHz–12.4 GHz) at the temperature range of 298 K–573 K with a thickness of only ∼2 mm. Moreover, attenuation mechanism and evolution of the microwave absorption properties for the FeCo@ZnO flaky material at elevated temperature has been clearly disclosed by the composition and microstructure characterizations, electromagnetic performance measurements and first principles calculations for the first time. Moreover, the Poynting vector, volume loss density, magnetic field ( H ) and electric field ( E ) are simulated by HFSS to understand the interaction between EM waves and the samples at different temperatures, further elaborating the attenuation mechanism in high-temperature environment. This study provides guidance in designing and developing high-temperature microwave absorbers for the next generation.

Metamaterial-Loaded 16-Printed Log Periodic Antenna Array for Microwave Imaging of Breast Tumor Detection

This article presents printed log periodic antennas with metamaterials for use in microwave imaging. A single layer of epsilon negative (ENG) metamaterial (MTM) array (1 × 6) of the unit cell is on the radiating patch. Adding a single negative metamaterial structure enhances the properties of far-field antennas, such as radiation pattern and gain, both of which are vital for breast imaging. Two frequency bands exhibit negative permittivity: 3–3.3 GHz and 3.6–4.5 GHz. In the operating band, the proposed antennas have achieved a maximum gain of 5.5 dBi and impedance bandwidth of 3 GHz (2–5 GHz) with a reflection coefficient less than −10 dB. At the lowest operating frequency of 2 GHz, the electrical dimensions of this designed antenna are 0.34λ × 0.26λ × 0.01λ. All 16 transceiver antennas are arranged vertically in a circular pattern around the phantom, each acting as a transmitter and the rest as receivers. The system design is carried out with the electromagnetic simulators CST and HFSS. After receiving the extracted data, the data are postprocessed using the MATLAB software and the delay multiply and sum (DMAS) imaging algorithm. Based on the reconstructed image, it is evident that the MTM-loaded antenna-based imaging system can detect many undesired tumors inside the breast phantom.